1. Field of the Invention
This invention generally relates to a filler valve for a container filling machine, and more particularly, to a filler valve for a machine for filling beverages into containers such as bottles, cans etc. under a counterpressure. The filling machine can have a tank or reservoir which contains the filler valve therein. The filler valve has a valve closing body for opening and closing a fluid filling passage, and a gas, or vent pipe which can be raised and lowered and is guided inside the valve closing body. Such a filler valve can also have a centering bell which can be raised and lowered independently of the gas pipe to seal the mouth of the container to be filled against the surrounding atmosphere. The control movements of the valve, or of the movable parts of the valve, can be initiated at least partly by a rotary pinion gear, which rotary pinion gear can be actuated from outside the tank, or reservoir, by means of control cams.
2. Background Information
Such a filler valve is disclosed, for example, in German Laid Open Patent Application No. 2 126 113. That filler valve disclosed therein is a valve for filling beverage cans, whereby the liquid to be filled is under pressure, and a corresponding counterpressure is also established in the can to be filled. For this purpose, first the can is primed to the pressure prevailing in the reservoir, and after the pressure has been equalized, the filler valve, strictly speaking, is opened, so that the liquid in the reservoir, or tank, can flow into the can, under the influence of the geodetic gradient, or simply gravity flow. During the filling process, the liquid ascends to the lower opening of the gas, or vent pipe, whereupon the remainder of the filling process stops automatically, because there can be no reverse exchange of gas from the container or can back into the reservoir. At this juncture, there can typically be a release of the pressure in the can, which can then be removed from the filler valve and closed.
In this known filling apparatus, the can can be sealed to the filling element by means of a centering bell, which works with a differential pressure chamber, and by means of the differential pressure chamber, the bell gasket is pressed against the mouth of the container during the filling process. On this can filler valve, the gas pipe is guided so that it can move inside the filler valve body. However, the gas pipe has a rigid connection to the centering bell, so that the end of the gas pipe always projects a certain distance beyond the lower edge of the centering bell as a function of the desired filling level. Consequently, the stroke movement of the centering bell must be greater by at least this projecting distance of the gas pipe, so that during the introduction of the can under the centering bell or under the filling element, a certain space is left open between the bell or the lower edge of the gas pipe and the upper edge of the can. This larger space leads to undesirably large pressure reduction volumes.
On another can filler valve, as disclosed in German Laid Open Patent Application No. 37 25 609, which valve also works with a differential pressure chamber, the gas pipe is mounted independently of the centering bell which can be moved up and down, so that only a small stroke movement is necessary to lower the centering bell. However, on this valve, the final lowering of the gas pipe into the lower position is done by opening, or lowering the closing body. Therefore, during the closing, or raising of the filler valve, the gas pipe is also raised by the amount of the closing stroke, and a subsequent change of the final fill level is thereby effected as additional air can then leave through the gas pipe, thereby allowing additional fluid to flow into the can. Movement of the gas pipe is thereby actuated by a piston-cylinder system, and the movement of the filler valve body is executed by an externally actuated fork of a pinion gear control.